Oddbean new post about login | logout "If you hold something sensitive on Telegram and it's not encrypted, you MUST take appropriate action." There's no guarantee that content actually gets deleted when you press the button in Telegram, right? What about account deletion? What other measures do you recommend aside from choosing a better app?
Can't really be sure if it is gone, it's gone. Users should just hope for the best. Deleting account on it's own would not delete their messages, they need to do that themselves, either by clearing DMs for both individuals or erasing their messages. If they want to delete their account, they should do that first. It's a user's choice to do that.